Not sure if this is normal or not. All I did was install a throttle body that came off a '93 3.3L V6. It's visually bigger and larger than the port on the intake manifold. I trimmed the gasket to fit the TB, but there is still the lip into the intake manifold. Since the intake manifold itself didnd't change I wasn't expecting the boost levels to really change. So with stock TB is hit 10lbs of boost by 3500RPMs and pulled nice through the gears. After the larger TB was installed it struggles to hit 7lbs of boost and it obviously down on power. I put the stock TB back on for now, but is that to be expected? I know guys with superchargers when you open up the intake side the boost levels usually go down due to better flow but the power goes up as the overall volume of air increases. That didn't happen in this case.